1. Field
The present invention relates to improvement of a straddle type vehicle equipped with an air cleaner.
2. Description of the Related Art
A type of straddle type vehicle is known in which an opening for taking in air is provided in the vicinity of a head pipe, and air taken in from the opening is introduced to an air cleaner arranged between paired left and right main frames (see, for example, FIG. 4 of Japanese Patent Publication No. 2006-46301 (Patent Document 1)).
As shown in FIG. 4 of Patent Document 1, a body frame (1) (the bracketed number indicates a reference numeral used in Patent Document 1; the same shall apply hereinafter.) includes a head box (3) integrally including a head pipe portion (2) and having a Y shape in plan view, and paired left and right main frames (5, 5) joined to a bifurcated rear portion of the head box (3). An air intake duct (35) is connected to a front end opening (3a) of the head box (3). Air taken in from a front end opening (35a) of the air intake duct (35) passes through the air intake duct (35), is exhausted from its rear end opening (35b), and is introduced to an air cleaner (20) arranged between the paired left and right main frames (5, 5).
The paired left and right main frames are preferably formed hollow to ensure frame rigidity and reduce weight. In some cases, an air cleaner of a large capacity is required in such a structure where the air cleaner is arranged between the hollow and highly rigid paired left and right main frames. However, if a larger capacity air cleaner is to be arranged between the hollow frames, the dimension of the paired left and right main frames will be increased in the vehicle width direction, which may lead to increase in the vehicle width.
It is desired to develop a straddle type vehicle capable of ensuring preferred frame rigidity and sufficient capacity in the air cleaner while avoiding drastic increase in the vehicle width.